The EU is pursuing multiple international companies over attitudes towards tax, including Apple, McDonald's, and Fiat. Many countries, such as Luxembourg and the Netherlands, have been ordered to recoup millions in lost tax revenue.

The investigation into Apple has been extended and expanded after the EU sent another bulky set of questions to the Irish government, according to the report. "We do not expect any decision until after the new year," said a spokesperson for the Irish finance ministry.

Apple has its European headquarters in Ireland, which houses over 5,000 employees. The company has come under fire in other European countries for paying little, or no, tax. The Daily Mail reported that Apple paid just £11 million ($16 million) in the UK despite making over £1.9 billion ($2.8 billion) in profit during 2014. The company paid the same amount the previous year.

Some lawyers have suggested the extension, which is due to the larger volume of questions, may be linked to the upcoming general election in Ireland, expected to be held in February.

The result of the Apple case could be a key issue in the election, according to The Financial Times.